Switch



March 25, 1930.- E. D. TREANOR SWITCH Filed Feb. 8, 1929 P O W n n 4 mm P we m 2 F Wu mm I H W d y b gg M 25, lddtl ID. TREANGR, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR T GENERAL ELECTRIC COMFANY, A CORPORATION OF NEW YORK SWITCH Application filed February 8, 1929.

invention relates to switches and its general object is to provide an improved switch adapted for changing tap connections of a transformer, although the improved sw"'" h is not limited to this use.

Many transformers are operated under conditions which require that the voltage ratio be adjusted or varied at intervals. This is usually made possible by providing on the transformer windings with taps ch are connected to a suitable switch so rtain of he turns or the winding may i of: out of circuit as desired, thus he effective number of turns in this switch is usually imt e same casing with the the tap leads may be as and to avoid the necessity leadsthrough the wall or the casing. A. switch of this character must have good current carrying anacity and its contacts must be well insushould also be as compact as pos- 1 because the space available is often very nited. I is an object of this'invention to ovide an improved switch having these esirable features.

[it-her objects and advantages will appear rein following description taken in conction with the accompanying drawing in ch Fig. 1 is a longitudinal sectional view switch constructed in accordance with the invention; Fig. 2 is a sectional view on the line 2-6 of a 1; Fig. is a view of an oil t 'ormer partly section. and provided e tap switch shown in Figs. 1 and and 4 is a diagrammatic view showing the conn ctions between the tap switch and one or" the transformer windings. Like reference characters indicate similar parts in the different views of the drawing. The switch as shown in the drawing has a cy indrical insulating casing 10 which encloses and supports the operating mechanism the switch. This casing may be supported any suitable manner with a transformer inside the transformer casing 12 as indicated in 8. A base member 13 which may be of moulded insulating compound, is sc Serial No. 338,515.

cured in the lower end of the casing 10. The base member 13 has integral upwardly projecting hollow studs 14 and fixed conductive contacts or posts 15 extend from the upper ends of these studs. Tap leads 16 from one of the transformer windings extend through the base member 13 and the studs 14 and are connected to the contacts 15. The studs 14 and contacts 15 are uniformly spaced about the axis of the switch.

The switch has a movable portion which fits loosely enough in the upper part of the casing 10 to be moved easily toward or away from the fixed contacts 15 and to be turned easily in either direction about its own axis. This movable part of the switch includes at each end an insulating support 17 having a central hub 18 and spaced radial extensions 19. The extensions 19 correspond in number and spacing to the fixed contacts 15 and studs 14 so that the movable part of the switch may be moved down until its lower or inner end support 17 is close to the base 13 with the studs 14 and contacts 15 projecting up through the spaces between the radial extensions 19 oi the inner end support 17.

The hubs 18 of the end supports 17. have central openings through which extends a metal tie rod 20 having an offset 221 midway between the end supports 17 The hubs 18 are extended to bear against the shoulders formed by the ends of the ofiset 21. The end supports 17 may be secured in place on the rod 20 by a bolt passing through an opening 22 extending through the end supports and the offset 21.

The ofiset 21 extends into the space between two of the contacts 15. A plurality of pairs of contacts 23 are disposed beside the offset 21. the two contacts of each pair being on opposite sides of the offset and pressed apart by a spring 24 passing through an opening in the offset. Two stops 25 limit the separation of the contacts 23 of each pair and, together with the springs 24, help to support the contacts. The two contacts 23 of each pair are conduct-ively connected together by a metal strip 26 extending around the 0dset part of the rod 20. these strips 26 also helping to support the contacts. The two stops are formed from a single metal plate, the ends of the stops being connected by top and bottom integral flanges 27 bent at right angles to the stops and clamped between the hubs 18 and the end shoulders of the offset 21 to support the stops.

The offset 21 has a projecting Wedge-shaped guide 28 at its lower end and the upper ends of the fixed contacts 15 are conical or rounded. The distance of the guide 28 from the axis of the switch is the same as that of the contacts 15 so that it may enter the space between two adjacent contacts and assure a proper angular position of the movable part of the switch with relation to the contacts.-

The stops 25 limit the separation of the contacts by the springs 24 so that the distance between the outer orcontact surfaces of each pair of contacts is slightly greater than the distance between any two adjacent fixed contacts 15. Thus, when the switch is closed, the contacts 23 will slide along the adjacent sides of two of the fixed contacts 15, the springs 24 being slightly compressed but pressing the fixed and movable contacts firm- 1y together and establishing a connection between the two fixed contacts. The outer edges of the stops 25 are curved to engage the two fixed contacts 15 which are connected by the movable contacts and to support these two fixed contacts against the side pressure due to the springs 24.

It is obvious from 4 that any two adjacent fixed contacts 15 may be connected together depending upon the angular position of the movable part of the switch and that the number of efiective turns in the tapped winding of the transformer will depend upon which two of the contacts 15 are connected together. All of the fixed contacts l5 except the two which are connected together are idle and carry no current. These small. Compactness, however, requires a close spacing of the contacts 15. Additional insulation is therefore provided for the idle contacts 15 by hollow insulating cylinders 29. These cylinders 29 are secured between the end supports 17 and in line with the spaces between the radial extensions 19. There is, of course, no difference involtage between the two contacts 15 which are connected together andtherefore no insulating cylinders are provided in the two positions adjacent to the movable contacts 23. When the switch is closed, the insulating cylinders 29 also extend well above the upper ends of the fixed contacts 15. The idle fixed contacts are thus efiectively insulated from each other and from the other two contacts 15 which are connected together. The switch is operated by an insulating rod 30 connected to the center rod-20 of the movable part of the switch and extending throughthe cover ofthe transformer casing.

The invention has been explained'b describing and illustrating a specific em odiment thereof but it will be apparent that various changes may be made without departing from the scope of the invention as defined in the appended claims.

What I claim as new and desire'to secure by Letters Patent of the United States, is:

1. 1A switch including-a plurality of fixed contacts, means for connecting together two of said contacts, and means for insulating the remainder of said contacts from each other and from said two contacts, said contacts and said connecting and insulating means being relatively movable. I

' 2. A switch including a base with spaced contacts projecting therefrom, a movable rod, spaced supports carried by said rod, means carried by said rod for connectin together two of said contacts, and hollow insulating. cylinders carried by said spaced su ports for insulatin the remainder .of said contacts from eacli other.

3. A switch including a base having hollow projecting insulating studs,'contacts protogether two of said contacts, hollow insulatj ecting from said studs, means for connecting ing cylinders for insulating the remainder of said contacts, and a common movable supporting means for sald. contact connectlng.

means and insulatin cylinders.

4.. A switch including a base having hollow projecting insulating studs, contacts projecting from said studs, said studs and contacts being uniformly spaced about a common axis means for connecting together two of sai contacts, hollow insulating c linders for insulating the remainder of said contacts, and a common supporting means forsaid contact connecting means and. insulating cylinders said. supporting means bein movable towar and from said contacts, an angularly, about their commonaxis.

. 5. A switch including a tacts uniformly spaced about a common axis, a'rod, two spaced end supports carried by said rod, said rod having an ofi'set between said end supports, contact means carried by said offset, insulating cylinders carried by said end supports, said rod being movable" plurality of I con 11" tacts uniformly spaced about a common axis, a rod movable longitudinally and angularly, spaced end supports carried b said rod, said rod having an offset, conductively connected 5 contacts on both sides of said oflset, a sprin for separating said conductively connected contacts, stops for limiting the separation of said contacts, and insulating cylinders carried by said end supports. 8. A switch including a plurality of contacts uniformly spaced about a common axis, a rod movable longitudinally and angularly, said rod having an offset, conductivel connected contacts on both sides of said 0 set, a spring for separating said conductively connected contacts to force them against two of said uniformly spaced contacts, and means for supporting said two contacts against the pressure due to said spring. 9. A switch including a plurality of contacts uniformly spaced about a common axis, a rod movable longitudinally and angularly, said rod having an ofiset, conductivel connected contacts on both sides of said ofl set, a spring for separating said conductively connected contacts to force them against two of said uniformly spaced contacts, and means forguiding said offset and conductively connected contacts between said two uniformly 3o spaced contacts.

In witness whereof, I have hereunto set my hand this 6th da of Feb. 1929.

EDW RD D. TREANOR. 

